ISHS Acta Horticulturae 98: Symposium on Research on Recirculating Water Culture
STUDIES ON THE CONTROL OF LETTUCE BIG-VEIN DISEASE IN RECIRCULATED NUTRIENT SOLUTIONS |
| Authors: | J.A. Tomlinson, E.M. Faithfull |
| Abstract:
Lettuce big-vein disease is transmitted from diseased to healthy plants by zoospores of the root-infecting fungus Olpidium brassicae. A laboratory technique for assaying the toxicity of chemicals to zoospores showed that the zoospores were killed in dilute preparations of carbendazim (methyl-2-yl-benzimidazole carbamate) as Bavistin (BASF 3460F) and in a formulation of Bavistin containing no carbendazim. As the latter formulation probably contained surfactants, different surfactants were tested and several found to be toxic to zoospores at concentrations of 1–10 ppm. These included Agral, Cetrimide, Deciquam 222, Ethylan CPX, Hyamine 1622, Manoxol/OT and sodium lauryl sulphate. When applied to the recirculated nutrient solution every four days Agral, at a concentration of 20 ppm, controlled the disease in a glasshouse lettuce crop grown by the nutrient film technique. Bavistin, at a concentration of 0.025 g per block, controlled the disease and prevented Olpidium root infection of lettuce grown in 4.3 cm3 peat blocks containing Olpidium resting spores. | |
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